Geobge lee andeks



(No Model.)

- G. L. ANDERS.

TELEPHONIG SYSTEM.

No. 287,356. Patented Oct. 23, 1883.

UNITED STATES PATENT OFFICE.

GEORGE LEE ANDERS, OE BOSTO N, MASSACHUSETTS, ASSIGNOR TO AMERI- CAN BELL TELEPHONE COMPANY, OF SAME PLACE; n

TELEPHONIC SYSTEM.

SPECIFICATION forming part of Letters'Patent No. 287,356, dated October 23, 1883.

Application filed October 7, 1880.

circuit, and with a battery and variable re- I 5 sistance-transmitter in the main line, of a key for cutting out (by shunting or short-circuiting, for example) the said transmitter when not in use, so as to diminish the resistance of the line.

The invention also consists in the combination of the armature of the call-bell hammer with the magnetic core of the induction-coil, thus obviating the necessity of a special electro-magnet for the call-bell and reducing the number of devices necessary in a telephonic system.

The accompanying drawing is a diagram representing a line in which the connections at the several stations are arranged in accordance with my invention.

' In this diagram, A is the microphonic transmitter.

B is the induction-coil, one terminal of whose primary circuit is connected to the line out and the other to the transmitter, and C is the receiving-telephone, which is connected to the terminals of the secondary circuit of the induction-coil.

D is the battery, which may be placed at 4o any point in the circuit.

(No model.)

The receiving-telephone shown is the ordinary well-known hand-telephone, consisting of a permanent magnet with pole-pieces carrying coils of fine insulated wire and a vibratory diaphragm of iron in front of the magnetic poles.

In order to avoid the resistance of the transmitters, there is a key, E, at each station, by means of which the transmitter at said station is normally short-circuited, but can be put in circuit when it is desired to speak through the transmitter. This key can be operated by hand, or can be attached to the telephonesupport and operated automatically by the re moval of the telephone from said support. For the reason that the line-circuit includes the primary circuits of the induction-coils, the cores of each of said coils can be used for operating the hammer-levers of the call-bells.

What I claim as my invention, and desire to secure by Letters Patent of the United States,

1. The combination, with a line-circuit and a local circuit connected with each other through the intermediary of an induction-coil,

nesses.

GEO. LEE ANDERS.

Witnesses:

GEo. W. PIERCE, ALEX. L. HAYES. 

